Do all Wiccans belong to covens?

Sometimes the whole 'coven' concept is brushed aside as a stereotype, but many witches or Wiccans do belong to groups that we call covens. Some traditionalists say that you do need to belong to a coven in order to refer to yourself as Wiccan, but it's becoming more and more accepted that Wicca can be practiced alone. People who do not belong to a group are called 'solitaries'. Also, covens do not have to have 13 members, nor do covens always gather on full moons. Coven arrangements are quite variable and can range from a very structured group, to a loose and informal group.